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A widespread agricultural practice is an unexpected CO<sub>2</sub> sink

Nature作者：G. Philip Robertson2026年9月23日正文已收录本站
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‘Liming’ to reduce soil acidity has long been considered a carbon dioxide source, but in North America’s largest river basin, it has resulted in net capture of atmospheric carbon.

By

  1. G. Philip Robertson

    1. G. Philip Robertson is in the W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan 49060, USA, and the Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA.

  2. Stephen K. Hamilton

    1. Stephen K. Hamilton is in the W.K. Kellogg Biological Station, Michigan State University, Hickory Corners, Michigan 49060, USA, and Department of Integrative Biology, Michigan State University, East Lansing, Michigan, USA.

Every year, more than 30 million tonnes of agricultural lime, comprising mainly calcium and magnesium carbonates, are applied to US croplands to maintain optimal soil acidity (pH) for plant growth. The United Nations Intergovernmental Panel on Climate Change (IPCC) considers this process, known as liming, to be a source of greenhouse-gas emissions because the chemical reaction through which lime, which is a source of alkalinity, neutralizes strong acids in soil also generates carbon dioxide1. However, writing in Nature, Suhrhoff et al.2 provide a comprehensive analysis of water chemistry in the Mississippi River basin and show that, overall, lime has been a substantial sink, not a source, of atmospheric CO2. This finding makes agricultural liming, in effect, a strategy for CO2 reduction.

doi: https://doi.org/10.1038/d41586-026-02646-7

References

  1. Intergovernmental Panel on Climate Change. 2006 IPCC Guidelines for National Greenhouse Gas Inventories (United Nations, 2006).

  2. Suhrhoff, T. J. et al. Nature https://doi.org/10.1038/s41586-026-11040-2 (2026).

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  3. Hamilton, S. K., Kurzman, A. L., Arango, C., Jin, L. & Robertson, G. P. Global Biogeochem. Cycles 21, GB2021 (2007).

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  4. US Environmental Protection Agency. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2020 (EPA, 2022).

  5. Robertson, G. P. In Encyclopedia of Agriculture and Food Systems 3rd edn, Vol. 1 (ed. Alexander, P.) 38–53 (Academic Press, 2025).

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  6. Power, I. M., Spence, J., Guo, M., Wilson, S. & Watmough, S. Proc. Natl Acad. Sci. USA 123, e2602421123 (2026).

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  7. Raymond, P., Planavsky, N. & Reinhard, C. T. Nature Water 3, 844–847 (2025).

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Competing Interests

The authors declare no competing interests.

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